Caption: Astronaut Bruce McCandless floats free above the Earth in his manned maneuvring unit (MMU) on February 7, 1984, during the 10th space shuttle flight (mission 41B). McCandless, who helped design the MMU, was the first person to fly it, thus becoming the first "human satellite" in orbit around the Earth. The MMU is propelled by small nitrogen thrusters which are controlled by the astronaut's hands. Because no umbilical cord attaches the astronaut to the spacecraft, it gives much greater mobility than was available to earlier spacewalkers. Mission 41B was launched from Kennedy Space Center on February 3, 1984, & landed back at Kennedy on February 12.